In some multi-cylinder diesel engines, conventionally, a crank shaft extends in the anteroposterior direction, a common rail which is directed in the anteroposterior direction is placed above an intake manifold, and an engine cooling fan is placed in front of the engine (see Patent Literature 1).
An engine of this type has advantages that heat of a cylinder head and a cylinder block is hardly transferred to the common rail, and that the common rail can be air-cooled by engine cooling air produced by the engine cooling fan.
In the prior art, however, an air intake portion of the intake manifold is placed in front of the common rail, and hence there is a problem.